A hybrid vehicle uses two distinct power sources to propel the vehicle, typically either an electric system or an hydraulic system to supplement an internal combustion engine in order to reduce its fuel consumption. There are appropriate applications for both electric and hydraulic hybrid systems, the value proposition and peak efficiency for each system depending on the vehicle duty cycle.
Hydraulic hybrids have much higher power capability, but for shorter periods, and typically regenerate more kinetic energy during braking than electric hybrid systems, which typically have greater energy storage capacity, but produce less power. Hydraulic hybrid systems typically recover up to 75% of the vehicle's kinetic energy compared to 25% for electric hybrids, and are capable of faster, more efficient energy charge and discharge than battery systems.
A problem, however, in hybrid vehicles is the need for the alternative mode of propulsion to provide the diverse requirements of optimum power and torque, particularly during acceleration, maximum driving range and maximum energy regeneration during braking. To try to solve this problem many patents have been filed disclosing various combinations and configurations for employing both hydraulic and electric systems in a vehicle to obtain the optimum performance characteristics of each system. A solution to the problem may also have applications in electric vehicles as a battery range extender.
The objective of the invention is a combined motor for use as a primary or supplementary motor in electric and electric hybrid vehicle applications with the capability to provide, in both propulsion and energy recovery modes, optimized performance and efficiency over the vehicle's duty cycle, and offering weight, space, cost and production efficiencies.